Bayesian IRT in JAGS: A Tutorial

Item response modeling is common throughout psychology and education in assessments of intelligence, psychopathology, and ability. The current paper provides a tutorial on estimating the two-parameter logistic and graded response models in a Bayesian framework as well as provide an introduction on evaluating convergence and model fit in this framework. Example data are drawn from depression items in the 2017 Wave of the National Longitudinal Survey of Youth and example code is provided for JAGS and implemented through R using the runjags package. The aim of this paper is to provide readers with the necessary information to conduct Bayesian IRT in JAGS.